The use of devices made from various polymeric materials, including silicone rubber and polyvinyl chloride (PVC) and the like, has achieved an important place in carrying out numerous surgical procedures. An important class of such devices consists of various wound drainage devices, surgical inserts and surgical tubing all of which are important in the removal of blood and other fluids from a surgical or wound site.
Generally speaking in the course of such procedures a tubular device made of some inert, usually polymeric material, must be inserted and positioned through body tissue and must allow unrestricted flow of blood through the device for up to several days. The presently available devices, especially those made of silicone, have undesirably high resistance to movement through tissue. A greater problem is an undesirably high level of blood clot formation inside drainage tubes, especially those made from silicone and PVC. Most serious of all, the clots which form, especially in silicone, are difficult to remove. These undesirable characteristics primarily derive from the fact that silicone rubber tubing has a very hydrophobic surface which is very poorly wetted by aqueous media. Devices made from PVC, although better performing than silicone, also have poorly wetted, nonslippery surfaces.
Thus it has been deemed desirable to develop a process which would allow one to coat the surfaces of devices made from various polymeric materials, such as for example silicone, PVC, latex, polyester, polyurethane, and thermoplastic elastomers, to improve the wettability and slipperiness of such devices, particularly under conditions encountered when such devices are employed in wound drainage applications.
Amongst the prior art in which the applicants are aware dealing with the problem of coating various polymeric materials in contact with human body fluids are the following:
U.S. Pat. No. 4,100,309 discloses a multistep method of applying a hydrophilic coating on a substrate.
U.S. Pat. No. 4,119,094 is related to U.S. Pat. No. 4,100,309 and claims articles coated in accordance with the process set out therein.
U.S. Pat. No. 3,925,178 discloses a process for treating a plastic contact lens to make the lens surface hydrophilic without changing the optical characteristics of the lens.
U.S. Pat. No. 4,312,575, also discloses contact lenses having an ultrathin, clear, lipid-permeable hydrophilic barrier coating which is formed by an electrical glow discharge process.
U.S. Pat. No. 4,589,879 teaches a method for coating vinyl tubing with PVP using DMF as a solvent. The coated product produced is however found to be distorted and the coating uneven and of very poor quality.
None of the foregoing references teaches the process or the products produced thereby which are the subject of the present invention.